Many different types of magnetic media have been developed to store information. Examples of such magnetic media include hard drives, magnetic diskettes, magnetic tapes, magnetic tape cartridges, magneto-optical disks. Increasing data storage density is desirable in the development of new or improved types of data storage media. Different multifunctional nanostructures are desirable for a variety of applications, including biomedical sensing, therapy, drug delivery, imaging, protein purification, cell separation, hyperthermia or their combinations. It is also desirable to simplify production and reduce production costs.